American Avalanche Association (AAA), The Organization of US Avalanche Professionals, Avalanche Terms: Avalanche/Snowpack Glossary of Useful Terms, USA 1999 (This glossary was scanned from a variety of print sources and reviewed & updated 2002). http://www.avalanche.org/moonstone/biblio%20&%20gl oss/AVALANCHE%20TERMS.htm, (ND/ Avalan/ Snowpack - Amer) {4}